A number of attempts have been made to replace incandescent and halogen bulbs with Light Emitting Diodes (LEDs) in various lighting applications because of their relatively small power consumption and long life. LEDs are more efficient than bulbs at converting electricity into light. LEDs are also durable and immune to filament breakage due to shock or vibration. When heat from the LEDs is properly managed, LEDs can last several times longer than incandescent or halogen bulbs. Accordingly, LEDs require less frequent maintenance and/or replacement compared to bulbs.
However, LED products are not without design challenges. LED systems require significant design efforts to keep component junction temperatures at acceptable levels. A high-power LED can generate a substantial amount of heat. Overheating could cause the LED system to fail prematurely and possibly damage other objects located nearby.
LEDs are frequently attached to circuit board materials that are poorly suited to dissipate heat. Also, most current LED mounting designs require heat to travel through multiple materials (LED, circuit board, heat sink) to reach the ambient environment. Thermal resistances occur through each material and at each junction between materials in the system. Any air gaps between materials add thermal resistance. The gaps can be eliminated, but not without expensive precision fabrication and mounting techniques. If materials are forced together, the resulting configuration could strain the LEDs or other circuit components, leading to system failure. In designs containing multiple LEDs, these challenges not only become increasingly difficult, but also contain LED position and assembly tolerance concerns. Solutions to these challenges are often costly and difficult to replicate.